Early expression of monocyte chemoattractant protein-1 correlates with the onset of isoproterenol-induced cardiac fibrosis in rats with distinct angiotensin-converting enzyme polymorphism.
BACKGROUND
Isoproterenol treatment of Brown Norway and Lewis rats (high and low plasma angiotensin-I-converting enzyme activity, respectively) results in similar cardiac hypertrophy but higher cardiac fibrosis in Brown Norway rats.


METHODS
Rats were infused in vivo with isoproterenol for two or 10 days. Cardiac fibrosis and inflammation were evaluated histochemically. We measured the mRNAs of pro-fibrotic factors (transforming growth factor beta(1), endothelin-1) and pro-inflammatory factors (monocyte chemoattractant protein-1). In studies with cardiac fibroblasts incubated with isoproterenol in vitro , we measured cell proliferation, angiotensin-I-converting enzyme and matrix metalloprotease 2 activities and deposition of collagen type I and fibronectin.


RESULTS
After treatment with isoproterenol for two days, there were large areas of myocardial injury and numerous inflammatory foci in the left ventricle, these being greater in Brown-Norway than in Lewis rats. After treatment with isoproterenol for 10 days, there were large areas of damage with extensive collagen deposition only in the left ventricle; both strains exhibited this damage which was, however, more severe in Brown-Norway than in Lewis rats. After treatment with isoproterenol for two, but not 10, days, greater amounts of monocyte chemoattractant protein-1 mRNA were found in Brown Norway than in Lewis rats. Cell proliferation, activities of angiotensin-I-converting enzyme and matrix metalloprotease 2, amounts of collagen type I and fibronectin were similar in cardiac fibroblasts from both strains; changes after isoproterenol (10 microM) were also similar in both strains.


CONCLUSIONS
We conclude that the greater cardiac fibrosis in Brown Norway rats treated with isoproterenol correlates with the early and higher expression of proinflammatory factors.
Copaja Soto
Miguel
M
Centro FONDAP Estudios Moleculares de la Célula, Universidad de Chile, Santiago, Chile.
Valenzuela
Rodrigo
R
Saldaña
Adiela
A
Paz Ocaranza
María
M
Jalil
Jorge E
JE
Vio
Carlos
C
Lijnen
Paul
P
Ordenes
Gamaliel E
GE
Vivar Sanchez
Raul
R
Lavandero
Sergio
S
Díaz-Araya
Guillermo
G
D000818:Animals; D006332:Cardiomegaly / Q000150:complications / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D005353:Fibronectins / Q000378:metabolism; D005355:Fibrosis; D005786:Gene Expression Regulation / Q000187:drug effects; D006352:Heart Ventricles / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D018836:Inflammation Mediators / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology*; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism
D018932:Chemokine CCL2; D019332:Endothelin-1; D005353:Fibronectins; D018836:Inflammation Mediators; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; D003094:Collagen; D007703:Peptidyl-Dipeptidase A; D020778:Matrix Metalloproteinase 2; D007545:Isoproterenol